In dogs and cats, the blood chemistry tests most commonly used to evaluate liver function are:

• A. Alanine transaminase and aspartate aminotransferase
• B. Electrolytes and blood urea nitrogen
• C. Gamma-glutamyl transferase and sorbitol dehydrogenase
• D. Amylase and lipase

Answer: (A)

Liver injury in dogs and cats is most often detected on a blood chemistry panel by measuring enzymes that leak out of damaged liver cells. The pair most commonly used for this purpose is alanine aminotransferase and aspartate aminotransferase. Alanine aminotransferase is highly liver-specific in these species, so when it rises, it strongly points to hepatocellular injury. Aspartate aminotransferase is also elevated with liver damage but is less specific because it is found in muscle as well, so it can rise for non-liver reasons. Using both together provides a sensitive indication of hepatocellular injury and helps monitor changes over time. Other enzymes listed serve different purposes: some indicate cholestasis or bile duct issues, some come from pancreas, and electrolytes with BUN reflect general metabolic status rather than direct liver injury. So, the combination of ALT and AST best represents the common approach to assess liver involvement in dogs and cats.